The incidence of hepatocellular carcioma (HCC) has doubled in the United States over the past two decades. Hepatitis C is the major risk factor for HCC with approximately 3 million individuals currently infected nationwide. Survival following HCC diagnosis is dismal except where potentially curative therapy (resection, transplant, local ablation) is applied. HCC surveillance is aimed at applying abdominal ultrasound and serum alpha-fetoprotein for diagnosing HCC at an early stage when patients are most likely to be eligible for potentially curative therapy. One randomized controlled trial and several cohort studies have indicated that HCC surveillance is associated with significantly improved survival. Practice guidelines have recommended HCC surveillance for patients with hepatitis C at high risk of developing HCC. However, there is a paucity of data evaluating the extent of prevalence, patterns, and determinants of HCC surveillance. AIMS: (i) To examine the patterns (prevalence, type, and frequency) of utilization of HCC surveillance in veterans infected with hepatitis C;(2) To examine patient-, facility provider-, and physician provider- determinants of HCC surveillance among veterans infected with hepatitis C;and (3) To examine the effect of HCC surveillance on the receipt of HCC potentially curative therapy and survival among veterans infected with hepatitis C, and to identify surveillance strategies associated with best outcomes. METHODS: We propose to conduct i) a retrospective cohort study of more than 150,000 patients infected with hepatitis C and 39,000 high-risk patients identified from the Department of Veterans Affairs Hepatitis C Registry, 2) a survey of more than 128 provider facilities to supplement information in the registry, and 3) a survey of physician providers to assess their knowledge and attitudes towards HCC surveillance. Surveillance tests will be identified in the registry based on a previously developed algorithm using data from administrative files. Patient-, tumor-, and facility determinants of HCC surveillance will be identifed from the Hepatitis C Registry and supplemented by the facility survey. Additionally, we will examine the association between surveillance and receipt of resection, transplant, or local ablation as well as survival. Hierarchical multivariable logistic regression and Cox proportional hazards modeling will be used to examine these outcomes. IMPACT: This study will examine a previously unaddressed subject pertaining to a highly fatal cancer that thus far has received little attention. It will provide information on the effectiveness of HCC screening as reflected by the extent of use as well as outcomes. Evaluating the extent and patterns of HCC surveillance is crucial in understanding diffusion (and obstacles) of this practice and in designing interventions to improve the implementation of HCC surveillance.